Spanish Journal of Agricultural Research
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Effect of green seaweed meal blend on feed quality and zootechnical performance in shrimp (Penaeus vannamei) juveniles
No full textAim of study: To evaluate a green seaweed meal in the diets of Penaeus vannamei juveniles, comprising Ulva spp., Caulerpa spp. and Enteromorpha spp. as a feed blend at inclusion levels at 4% and 8%.
Area of study: Universidad Nacional Agraria La Molina, Lima, Perú.
Material and methods: Analyses were conducted to determine the pellet quality through percentages of dry matter retention (DMR), protein loss and water absorption capacity; and to evaluate the effect of this seaweed meal in the digestibility and zootechnical shrimp performance. Three treatments (diets) were formulated to contain 0% (control diet), 4% (M4) and 8% (M8 of green seaweed meals (blend)), in isonitrogenous (crude protein; 300 g kg-1) and isocaloric (3.3 Mcal kg-1) diets. The shrimps were reared at a density of 286 juveniles m-3 for 29 days in a recirculating aquaculture system (RAS).
Main results: Among the diets, M4 had the highest DMR value (97.06%), whereas M8 had highest water absorption capacity (185.48%) with lower % of protein loss between the treatments diets. No differences were observed in the zootechnical performance, except for survival (p<0.05), with the M8 diet having highest mortality rate (44.4%) between the treatments diets.
Research highlights: Incorporating 4% green seaweed meal in shrimp feed supported adequate growth and survival of juvenile P. vannamei with adequate DMR values, water absorption capacity, protein loss and high apparent dry matter digestibility and apparent digestibility of the reference diet
Assessment of DSSAT and AquaCrop models to simulate soybean and maize yield under water stress conditions
No full textAim of study: To evaluate the performance of DSSAT and AquaCrop models in the estimation of soybean and grain maize yield under water stress conditions in a semi-arid region.
Area of study: Kermanshah, Iran.
Material and methods: AquaCrop and DSSAT were assessed to simulate soybean and maize. Both models were calibrated using field data. Field experiments were performed in a randomized complete block design with eight and four irrigation treatments for soybeans and maize, respectively with three replications. Measures of Normalized Root Mean Square Error (nRMSE) and Nash-Sutcliffe Model Efficiency were used to evaluate the accuracy of the models. For this purpose, simulated values of leaf area index / green crop canopy, grain yield, biomass, and soil moisture were compared with measured data.
Main results: Results indicated that the CROPGRO-Soybean in DSSAT software simulated more accurate crop growth of soybean than AquaCrop. The average nRMSE of the DSSAT model for estimating soil moisture, leaf area index, grain yield, and biomass were 6%, 14%, 16% and 20%, respectively. For maize, AquaCrop simulated crop growth more reliably than CERES-maize. The average nRMSE of 3%, 10%, 13% and 27% of the Aquacrop model in simulating the parameters of soil moisture, green crop canopy, biomass, and grain yield.
Research highlights: Considering the better performance of AquaCrop for maize and DSSAT for soybean in the study area, it is not possible to propose a specific model to simulate the growth of all crops in a region
Citrus crop performance and fruit quality in response to different scion-rootstock combinations
No full textAim of study: To address diversification of citrus cultivars to increase the variety and profitability of orchards to adapt them to environmental changes.
Area of study: State of São Paulo, a subtropical region of southeastern Brazil.
Material and methods: The study evaluated the phenological intervals, thermal sum, vegetative and productive performance, and fruit quality of the sweet orange cultivars ‘Rubi’ (R), ‘Lue Gin Gong’ (LGG) and ‘Valencia Delta Seedless’ (VDS) grafted onto 'Rangpur' lime (RL) and 'Swingle' citrumelo (SC). The field experiment was conducted over consecutive growing seasons 2018-2021.
Main results: The duration of the phenological intervals was little influenced by the rootstocks. The harvest time was approximately 245 days after anthesis (DAA) for R, 402 DAA for LGG, and 407 DAA for VDS, regardless of rootstock. Scion cultivars grafted onto RL showed larger canopy volumes and greater weight, length, and diameter of fruits than those of SC trees, and the combinations with SC were more productively efficient than RL due to lower canopy volume. The R scion cultivar presented superior yield performance and fruit colouration than LGG and VDS. The physicochemical quality of the fruits showed improved results with the combinations of LGG/RL, LGG/SC, VDS/RL, and VDS/SC.
Research highlights: These results may be useful when planning the diversification of scion/rootstock combinations for new orchards, identifying dual-market orange cultivars for industrial processing and natural consumption, and determining the combinations that are better adapted to undesirable climatic conditions
Fermented soybean meal in broiler diets exposed to stress induced by corticosterone: Effect on growth performance, gut health and immune response
No full textAim of study: To investigate the effect of fermented soybean meal (FSBM) on responses of broiler chickens exposed to stress condition.
Material and methods: Two hundred and eighty-eight day-old male chickens were allocated to six treatments in a 2 × 3 completely randomized factorial design involving two factors: factor 1 was the subcutaneous injections of CORT or corn oil (as control) at 2 mg/kg body weight twice per day during 3 days; and factor 2 were 3 levels (0, 10 and 20%) of FSBM in replacement of the original soybean meal.
Main results: The replacement of soybean meal by FSBM increased FI and BWG without any significant effect on FCR (10 days), while FCR was increased significantly by CORT injection. Corticosterone injection caused a significant decrease in the ratio of villus height (VH) to crypt depth (CD) in the duodenum and jejunum. The height of villi in the duodenum increased significantly at 20% FSBM replacement. The antibody titers against Newcastle disease (28 and 2 day), coliform count (28 day) and activity of digestive enzymes (10 day) were not affected by either FSBM replacement or CORT injections. Corticosterone injection significantly increased tall-like receptor-4 (TLR4) and immunoglobulin A (IgA) expression, while decreased heat shock protein-70 (HSP70) expression. FSBM replacement down-regulated the expression of TLR4, HSP70, and IgA in small intestine compared to the control group. In stress condition induced by CORT injection, 10% FSBM replacement decreased HSP70 and IgA expression in the jejunum and ileum, while had no effects on TLR4.
Research highlights: Partial replacement of soybean meal by FSBM in diets had positive effects on performance, intestinal morphology and immune response in chicks exposed to stress
Pistachio nut diffusion in Spain: Growth models
No full textAim of study: To analyse the diffusion of the crop by producing forecast models, that intend to help farmers in their decision-making.
Area of study: Spain. The area dedicated to pistachio cultivation in Spain has multiplied by 36 in the period 2010 to 2020, reaching 44,244 ha.
Material and methods: This study brings together data on the evolution of pistachio cultivation based on the following parameters: cultivated area, yield, and price. Methods are based on internal, external influence models and on an influence-price-crop yield pattern.
Main results: The results indicate that given a constant crop yield, raising pistachio prices, will bring a production increase that generate the saturation level of the system. Similarly, with a constant pistachio price and an increment of the crop yield, the saturation level of the system increases. Regarding the pattern of influence, it is shown that in a context of suitable market prices for pistachio and an optimal synergy of the production factors that favour the crop yield not only increases the level of saturation of the system but also the duration of the diffusion process.
Research highlights: The diffusion curve is sigmoidal with a well-defined inflection point and three well-defined phases. The adoption of pistachio in Spain responds to a model of internal influence (logistic) and never to models of external influence. According to the results, the process has a zero-innovation effect, while the dynamics of the process is completely determined by an imitation effect
Trends and gaps in tomato grafting literature: a systematic approach
No full textAim of study: To investigate the trends and existing research gaps in tomato grafting by employing scientometric methods.
Area of study: In silico at SCOPUS database.
Material and methods: Research articles were retrieved by combining the search terms related to tomato and grafting. The articles were selected according to pre-established criteria. Temporal trends and scientometric indexes were determined. Bibliometric mappings were conducted to determine the main countries, authors, and journals that published articles on tomato grafting; and to acquire collaboration and keywords co-occurrence networks. Technical aspects of tomato grafting were analyzed.
Main results: A total of 397 research articles published from 1944 to 2020 were analyzed. The number of publications on tomato grafting increased at an annual rate of 8.8%. The USA and Spain are notable in terms of the number of published and cited articles. The USA and European countries had the highest number of collaborations. European authors had the strongest research connections. Interspecific grafts (61.83%) and experiments in controlled conditions (82.87%) predominated. The growing interest in tomato grafting has been observed as a means of overcoming environmental issues as well as yield and quality improvement.
Research highlights: Collaboration among research groups contributed to a higher research impact on the theme. The mitigation of abiotic stresses and fruit quality has risen as significant concerns for tomato crops
Development of an electronic profilometer to measure mobilization variables in soil harrowing
No full textAim of study: This experiment's objective is to develop an automatic data acquisition system for profilometry, evaluating four harrowing speeds.
Area of study: Federal University of Parana, Curitiba, Brazil.
Material and methods: We experimented at the laboratory using a completely randomized design, comparing the data of modified roughness, raised and mobilized area, blistering, and thickness. These were acquired with traditional and electronic profilometers in seven replications. We executed the field test in lines, using a completely randomized design. The profilometers were in the plots and the targeted speeds in the subplots. We submitted the data for analysis of variance and when significant, to Tukey's test and regression analysis.
Main results: Laboratory testing showed no significant difference in the parameters of modified roughness, elevated and mobilized area, blistering, and thickness, denoting the phase validation that indicates applicability in the field. The field testing presented superior results for the electronic profilometer in elevated and mobilized areas and soil layer thickness. That is due to the absence of interference in the measurements that occur in the conventional profilometer caused by the insertion of the rods in the soil.
Research highlights: The increase in the mechanized set speed provided the reduction of the elevated area and soil blistering caused by the rise in disc rotation and consequent deviation of the soil particles
Effect of feeding restrictions on development of juvenile cobias, Rachycentron canadum
No full textAim of study: A 45-day trial was conducted to evaluate fasting as a possible way of food strategy during production of juvenile cobias (Rachycentron canadum).
Area of study: The study was conducted in the State of Espírito Santo, Brazil.
Material and methods: The following different protocols were used to organize their feeding: C, fish fed to satiety twice a day for 45 days; U1, fish fed to satiety twice a day on alternate days; U2, fish fed to satiety twice daily for five consecutive days, followed by two days of food deprivation, cyclically; U5, fish subjected to food deprivation for five days and then fed to satiety twice a day for 40 days; U10, fish subjected to food deprivation for ten days and then fed to satiety twice a day for 35 days; and U15, fish subjected to food deprivation for fifteen days and then fed to satiety twice a day for 30 days.
Main results: No mortality was observed during the trial period. The different feeding protocols significantly affected juvenile cobias development and wellbeing. The final weight (g) of cobia juveniles was C – 91.9 ± 9.1; U1 – 75.0 ± 11.2; U2 – 72.2 ± 6.0; U5 – 70.3 ± 6.1; U10 – 63.4 ± 4.6; U15 – 54.4 ± 4.7. No compensatory growth was observed during the entire experimental period.
Research highlights: Continuous fasting had a more severe effect than intermittent fasting. Significantly greater hepatocyte counts were correlated with longer fasting periods. Fasting protocols should not be recommended for juvenile cobias
Analysis of operating speed and power consumption of a gear-driven rotary planting mechanism for a 12-kW six-row self-propelled onion transplanter
No full textAim of study: To determine the optimal working speed of a gear-driven rotary planting mechanism for a self-propelled riding-type onion transplanter in order to choose an adequate forward speed for effective onion (Allium cepa L.) seedling planting.
Area of study: Daejeon, Korea.
Material and methods: The gear-driven rotary planting mechanism was composed of six planting hoppers that received free-falling onion seedlings through the supply mechanism and deposited them into the soil. To determine the optimal working speed for accurate transplantation of the seedlings, mathematical working trajectory modelling of the planting mechanism, virtual simulations, and validation field experiments were carried out.
Main results: According to the model simulation, a forward speed of 0.15 m s-1 of the transplanter and a rotating speed of 60 rpm of the planting mechanism were favourable for seedling uprightness and minimum mulch film damage. For the proposed transplanting mechanism, the free-falling distance was calculated as 0.08 m, and the accuracy for the seedling deposition into the hopper was demonstrated as 97.16% through the validation test. From the field tests, a forward speed of 0.15 m s-1 combined with a transplanting frequency of 60 seedlings min-1 was found to be optimum for obtaining a high seedling uprightness (90o), a low misplant rate (7.66%), a low damage area on mulch film, and low power consumption (36.53 W).
Research highlights: The findings of this research might be helpful in improving the design of the onion transplanting mechanism and accelerating the automation process for seedling transplantation.
 
Use of multivariate analysis and machine learning methods to characterize traits contributing to wheat yield diversity
No full textAim of study: Regarding the third largest staple food crop in the world, determining the factors affecting wheat yield is of great importance. This study aimed to determine useful subsets of agronomic traits and evaluate the order of importance of traits in grain yield.
Area of study: Fars province, Iran.
Material and methods: In total, the data corresponding to 22 agronomic traits was collected from six different regions (Darab, Kavar, Marvdasht, Fasa, Lar, and Khonj) of 90 farms of Fars province, Iran as the most important wheat-growing regions. Multivariate statistical analysis (correlation, stepwise regression, and principal component analysis (PCA)) and machine learning modeling approaches, such as partial least squares regression (PLSR) and support vector regression (SVR) models, were applied to agronomic traits.
Main results: The findings, based on integrated approaches such as correlation, stepwise regression, and PCA, highlighted that number of spikes m-2, grain number spike-1, and thousand-grain weight had a major impact on the yield followed by awn length, spike length, narrow leaf herbicide, broadleaf herbicide, time to plant maturity (month), and soil salinity. Besides, PLSR with nine inputs (nine selected traits) displayed better prediction capability (R2=85 %, RMSE=0.32, MSE=0.10, and BIAS=-0.05) than that with all twenty-two input traits.
Research highlights: Integrated multivariate statistical analyses and machine learning regression methods could be a powerful tool in determining traits that have a significant impact on yield. These achievements can be considered for future breeding programs